In the science of dentistry, die models of teeth and jaw portions are often used for making complex prosthodontic appliances, such as bridgework, crowns, and the like. This is accomplished by making an impression mold out of a quick-setting impression material around the actual teeth of a patient, thus duplicating the patient's anatomical structure. Thereafter, models of the teeth and jaw portions are reproduced from the impression, which is then utilized in the building of the dental prosthesis.
Throughout the fabrication procedure, it may become necessary to separate various portions of the model into sections. To facilitate this, several dowel pins, typically made of brass, may be inserted into the base of the die model, at least one in each area to be removed from the rest of the model.
For example, individual preparations of the model and their contacting tooth surfaces may each be penetrated from the base with one or more dowel pins. It should be noted at this point, that it is not desirable that all the die model be made to be removable. For non-removable portions, a retentive anchor is affixed to the model in the same manner as that of the dowel pins.
The model is then coated with a separating medium, and the dowel pins are encapsulated in a dental stone matrix. The model is then cut apart so that each section can be worked on independently from the rest of the model.
In preparing the die model for insertion of the dowel pins and retentive anchors, the model must first be ground to proper specifications. After this procedure, it is imperative that the holes for the dowel pins and retentive anchors be drilled at an exact angle, which is generally perpendicular to the base surface of the model. Also, the maximum depth of the hole must be a precise distance, for example 1/4 inch. If the holes are drilled too deeply, or if their angular direction is other than that which was intended, the model may be ruined.
In accordance with this invention, removable drill guide attachment is provided for drills, especially dental drills, to facilitate the drilling of holes in models and the like in the precisely desired direction, for a precisely desired maximum length. Thereafter, the attachment may be removed, to permit use of the dental drill for other purposes.